Data over opinions

In 1854, London was devastated by a cholera outbreak. While city officials debated theories about “bad air,” physician John Snow did something different—he mapped every death and traced them back to a single water pump. His data-driven approach not only ended the outbreak but revolutionized how we understand disease. Snow didn’t ignore expert opinions; he just knew that evidence trumps assumptions.

In UX design, we face similar situations every day. Stakeholders have strong opinions, designers have intuitive hunches, and everyone “knows” what users want.

When teams rely too heavily on opinions, they start designing for themselves instead of their users. The loudest voice in the room becomes the user’s voice. Personal preferences get mistaken for user needs. Before long, products reflect internal politics rather than external reality.

That’s what this value is about. While opinions and intuition help us generate ideas, data helps us validate whether those ideas actually work for real people.

What really matters in data-informed design is:

• Collecting both quantitative patterns and qualitative insights
• Understanding what the data means, not just what it says
• Using evidence to challenge assumptions (including our own)
• Knowing when to dig deeper and when to act

We should trust our design instincts enough to form hypotheses, but rely on user data to test whether we’re right. The best solutions come from combining human intuition with human evidence.

UX is about serving real users, not winning internal debates.